This was a prospective, randomized study conducted in three tertiary referral hospital in Korea. Three endoscopists performed the ERCP who had ERCP experience more than ten years From October 2010 to August 2012, ERCPs were performed on patients with pancreatobiliary diseases at Soonchunhyang University Seoul Hospital, Hanyang University Guri Hospital and Kosin University Gospel Hospital. Bile duct cannulation was attempted for various reasons (removal of bile duct stones, biliary stenting, cytology of bile, biopsy of the bile duct, etc.).